This section is intended to introduce the reader to various aspects of the art that may be related to various aspects of the present invention. The following discussion is intended to provide information to facilitate a better understanding of the present invention. Accordingly, it should be understood that statements in the following discussion are to be read in this light, and not as admissions of prior art.
The Voice Call Continuity (VCC) is an IMS application server that provides the following functions:                Enable IMS users to originate calls while roaming in 2G/3G network while maintaining their services and features in IMS.        Enable the delivery of calls for an IMS user while roaming in 2G/3G network.        Anchors the IMS call and provide the functionality required for inter-technology handoff of a call from IMS/LTE to 2G/3G.        
Based on the current VCC 3GPP2 standard, the mobile is programmed with the VCC VDN (Virtual DN) and the following procedures calls for the use of the VDN to perform:                Sending SMS Notification for Domain attachment to CDMA        Calling the VDN to perform in-call Handoff from LTE/IMS to CDMA        Calling the Emergency-VDN to perform LTE/IMS to CDMA on an emergency call in progress        
Additionally, the IMS subscriber has a limited profile in the HLR with WIN trigger that is used to trigger the call to be routed to IMS through the VCC. The address of the VCC to inquire for an IMS routing number is based on the point code of the VCC as stored in the subscriber's HLR profile.
The following are the issues with the existing solution:                The VDN #s are a hardcoded number in the Mobile and therefore the mobile is dedicated to one VCC server.        The # can only be preprogrammed on the phone or some method of the air provisioning has to be used.        Solution does not address Geo-Redundancy configuration.        Solution does not address VCC capacity growth and need to move users to new VCC.        Solution requires Emergency-VDN (provided by one operator) to be available in every roaming MSC.        Solution is not optimized for making calls when the mobile is roaming in a 2G/3G network.                    There is only one hardcoded VCC point code in HLR                        